android通过代码的形式来实现应用程序的安装与卸载

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    
    <Button 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="安装"
        android:onClick="install"
        />

    <Button 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="卸载"
        android:onClick="uninstall"
        />
    
</LinearLayout>

package com.njupt.install;

import java.io.File;

import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;

public class MainActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
	}

	public void install(View v){
		Intent intent = new Intent();
		intent.setAction(Intent.ACTION_VIEW);
		
		File file = new File(Environment.getExternalStorageDirectory(),"HtmlUI1.apk");
		intent.setDataAndType(Uri.fromFile(file), "application/vnd.android.package-archive");
		
		startActivity(intent);
	}
	
	public void uninstall(View v){
		
		Intent intent = new Intent();
	    intent.setAction(Intent.ACTION_DELETE);
	    intent.setData(Uri.parse("package:com.njupt.htmlui1"));
		startActivity(intent);
	}
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

}